Since the update to the latest version of camera raw, when selecting the crop tools then level tool, with precise cursors activated then the alignment line does not align with the centre of the cross hair, making it difficult to align the image correctly
On my Windows 10 system with Camera Raw 12.3 a horizontal alignment line drops down very slightly below the cross hair placement position. However, placing the line so it appears parallel to the horizontal object in the picture levels properly.
In the below example the cursor was placed at the top of the brown area. When the line was drawn it dropped slightly below that edge. Is that what you're seeing?